Hiya guys, I am having real trouble finding info so I thought I would bring it up here and see what wisdom I can find here.... I am restoring a 1915 Fiat car. It has a 2816cc side valve L head four cylinder engine. It does not have a detachable head. Has a water pump. 37mm inlet and exhaust valves (with scant room for larger ones) It has three white metal main bearings and no crank counter weights. It as an oil pump and pressure feed mains. In original condition it is said to have 28hp at 1850rpm. It has a stroke of 140 and a bore of 80. The whole engine is pieces and needing a full rebuild. Now I want to make the most of this engine with out making it break all the time.... To this end I have some ideas but you try finding info on how to get maximum go between 2000 and 2300rpm!! Finding info on engines spinning at 6000rpm to 10000rpm is easy to find.... but 2200 not so easy!! I welcome comments of the following ideas..... ############<WBR>#########<WBR>#########<WBR>#########<WBR>#########<WBR>#########<WBR>####### RELIABILITY. Crank. Weld on counter weights to the crank (easy as the crank webs are all square) my theory being it will run smoother and be able to maintain higher revs 2500 absolute max, without hammering out the mains, crank and flywheels balanced etc. Run a lightened fly wheel, to get revs to go up and down faster with less stress to the crank. Extra weight which was needed to dampen vibration of the old unbalanced crank will not be needed. Remaining flywheel will still be substantial in size. Cooling.. Run a temperature controlled electric fan with shroud over the rear of rad. Run extractors not the large cast iron exhaust manifold, to get heat away from the block. Rods.. Straightened, x rayed and polished. Oil pump. Look at any upgrades that can be done inside pump for more flow. ____________<WBR>_________<WBR>_________<WBR>_________<WBR>_________<WBR>_________<WBR>_ GETTING MORE GO... Get more air in... Fit a slightly later period brass bodied 1.5 inch (38mm)SU carb. The original is a odd system with fuel and air (with 36mm air throat) going in different places and mixing in the block. try and get a 38 or 39mm inlet valves in their Re grind cam for more go. Burn mixture with biggest bang.... Highest compression aluminum pistons I can have made. Twin plugs, good hot mag OR electronic ignition hidden inside a spare magneto shell?? Getting gas and heat out. The original exhaust manifold is a long cast iron thing where the gas has to go right along it to the rear to get out... so I am looking at making a subtle set of extractors for it in 1.5 pipe and a tail pipe 2 inch and not very restrictive modified original muffler. ############<WBR>#########<WBR>#########<WBR>#########<WBR>#########<WBR>#########<WBR>#########<WBR># Ok so that is my plan... now what huge holes are in it????? You will notice that I have avoided using the terms "torque" and "power" as these cause more confusion then good most of the time. Overall I am not wanting to hotrod the car... just make improvements that are no too hideous that will make the car more usable on modern roads. I am not going to high speed all the time, just better acceleration and usable "go" in real world road situations. Just don't mention the brakes!.... I am putting the car through a diet... and it has very lightweight bodywork to make the most of the "go and stop" it does have. So any ideas or things I have missed the point of?? Regards Gavin New Zealand
Sounds like you've got things thought out pretty well. Might want to be careful on high compression pistons, that block and head might not be able to handle a lot more than stock. Plus the added stresses to those old parts could be bad.
Sounds like a good plan. Does it have pressure fed big end bearings or just splash/dip fed? Can you get a long burr into the ports to open them up a bit? A rubberised harmonic balancer might be worth a go too. Any Pics?
i know a guy that can help you,his shop is in Northern California,they are one of the few shops that are qualified to do this sort of work. the local HET club took a tour of the place a couple years ago,they were working on Bugatti,Ferrari,Pegaso,even a 1914 Peugot racer.
It's a big job but you can make this run provided the basic stuff is good Not having the stuff in front of me we're going to talk general direction only I'd make new crank rods pistons just to get control of dimensions and material quality This way you can make the crank and rods full pressure and use thin-wall steel backed bearings. You'll need new main caps too and the bearings have to snap into the caps directly NO ADAPTORS The shell's big job is to hold the oil wedge, support the crank, and transfer heat away from the oil....... More layers of stuff(bronze spacer) less/slower heat transfer and sooner the oil breaks down ...... It's a flow/temp game If your making the crank you can also increase the radii This ups the cranks strength more than anyone will believe So that's the crank counter weights? if you want em but 2500 rpm no big deal. Rods ....... Again make them pick a real bearing. Keep the diameter small as you can. Since your making the crank you pick the rod width. I like long rods small wrist pins and a tight 3 ring package. Keep the piston skirt short If the rod is long the side load is lower and you don't get the slap if you place the pin high. You also get the piston dwell BDC and TDC closer better combustion and cylinder filling Last is the Cam lottsa lift not a bunch of duration High-Compression is OK but you'll find you can't get 12:1 easy And always get lots of good clean 80C oil to the bearings even if you must fit a external pump to do it. Hope that helps It been raining and I'm not really awake today
Re: "I'd make new crank rods pistons just to get control of dimensions and material quality " ... I think he may prefer not to sell his house to pay for this.
Two thoughts; 1. Magnaflux all the parts for cracks. 2. If you bore out the cylinders, have the block sonic checked to prevent poking through to the water jacket. Good luck!
on the cam front, I would recommend Bruce Crower in San Diego or Dema Elgin in Santa Rosa. I have had them grind a few low RPM cams that have come out very well. Long shipping for you, but it will probably be worth it in the end. Good luck. also you can make the car go very well with out jacking up the compression really far.
The Jalopy Journal
